Local hyperthermia therapy for cancer can produce selective heating of solid tumors on the basis of known physical laws. The goal of therapy is to achieve cytotoxic temperature elevations in the tumor for an adequate period of time, without damaging nearby normal tissues. As we have shown both experimentally and theoretically, a paucity of blood flow in the tumor or a surplus of blood flow in adjacent normal tissues can enhance selective tumor heating considerably. This proposal seeks support to investigate three promising techniques to enhance blood cooling of normal tissues surrounding a solid tumor in order to allow greater power input and in turn greater temperature elevation within the tumor. The three methods are (1) use of vasodilator drugs which act selectively on normal vessels to promote blood cooling of normal tissues, (2) hypothermic arterial perfusion, which increases the temperature gradient between blood and tissues to exploit existing blood flow differences between tumor and normal tissues, an (3) tumor vascular stasis following initial heat treatment, which makes subsequent heat treatments more effective. In investigating these three methods of enhanced hyperthermia therapy, we will monitor regional blood flow and temperature distributions in and around inductively heated experimental tumors in dogs, using the transmissible venereal tumor model. The research will be conducted by an interdisciplinary team including a physician/pharmacologist, a veterinary oncologist, and a mechanical and electrical engineer with expertise in heat transfer.